Complexes of abiraterone acetate, process for the preparation thereof and pharmaceutical compositions containing them

ABSTRACT

The present disclosure relates to pharmaceutically acceptable complex formulae comprising complexes of Abiraterone acetate and pharmaceutically acceptable excipients, process for the preparation thereof and pharmaceutical compositions containing them. The complex formulae of the present disclosure have improved physicochemical properties which results in reduced food effect which allows significant dose reduction and the abandoning of the requirement of taking the drug on an empty stomach.

This application claims the benefit of priority to application no. HUP1500055, filed Feb. 9, 2015, the disclosure of which is herebyincorporated by reference as if written herein in its entirety.

FIELD OF THE INVENTION

The disclosure is directed to a stable complex with controlled particlesize, increased apparent solubility and increased dissolution ratecomprising as active compound Abiraterone acetate, which is useful inthe treatment of a certain type of prostate cancer that has spread toother parts of the body. Abiraterone acetate might be used for earlierstages of prostate cancer and advanced breast cancer. More specifically,the complex of the present disclosure possesses increased apparentsolubility and exhibits no positive food effect which allows significantdose reduction and the abandoning of the requirement of taking the drugon an empty stomach. The disclosure also relates to methods offormulating and manufacturing complex according to the disclosure,pharmaceutical compositions containing it, its uses and methods oftreatment using the complex and its compositions.

BACKGROUND OF THE INVENTION

Abiraterone is a potent and selective inhibitor of CYP17(17α-hydroxylase/C17,20-lyase). As Abiraterone was poorly bioavailableand also susceptible to hydrolysis by esterases, a prodrug wasdeveloped. Abiraterone acetate (A) was found to be resistant toesterases and was rapidly deacetylated to Abiraterone (B) in vivo,resulting in potent CYP17 inhibition. Abiraterone acetate is designatedchemically as (3β)-17-(3-pyridinyl) androsta-5,16-dien-3-yl acetate andits structure is:

Abiraterone acetate is a white to off-white, non-hygroscopic,crystalline powder. Its molecular formula is C₂₆H₃₃NO₂ and it has amolecular weight of 391.55. Abiraterone acetate is a lipophilic compoundwith an octanol-water partition coefficient of 5.12 (Log P) and ispractically insoluble in water. The pKa of the aromatic nitrogen is5.19.

Inactive ingredients in the Zytiga® tablets are colloidal silicondioxide, croscarmellose sodium, lactose monohydrate, magnesium stearate,microcrystalline cellulose, povidone, and sodium lauryl sulfate.). EachZytiga® tablet contains 250 mg of Abiraterone acetate.

Abiraterone acetate (ZYTIGA) is converted in vivo to Abiraterone, anandrogen biosynthesis inhibitor, that inhibits17α-hydroxylase/C17,20-lyase (CYP17). This enzyme is expressed intesticular, adrenal, and prostatic tumor tissues and is required forandrogen biosynthesis.

CYP17 catalyzes two sequential reactions: 1) the conversion ofpregnenolone and progesterone to their 17α-hydroxy derivatives by17α-hydroxylase activity and 2) the subsequent formation ofdehydroepiandrosterone (DHEA) and androstenedione, respectively, byC17,20 lyase activity. DHEA and androstenedione are androgens and areprecursors of testosterone. Inhibition of CYP17 by Abiraterone can alsoresult in increased mineralocorticoid production by the adrenals.

Androgen sensitive prostatic carcinoma responds to treatment thatdecreases androgen levels. Androgen deprivation therapies, such astreatment with GnRH agonists or orchiectomy, decrease androgenproduction in the testes but do not affect androgen production by theadrenals or in the tumor.

Abiraterone acetate decreased serum testosterone and other androgens inpatients in the placebo-controlled phase 3 clinical trial. It is notnecessary to monitor the effect of Abiraterone on serum testosteronelevels.

Changes in serum prostate specific antigen (PSA) levels may be observedbut have not been shown to correlate with clinical benefit in individualpatients.

Following administration of Abiraterone acetate, the pharmacokinetics ofAbiraterone and Abiraterone acetate have been studied in healthysubjects and in patients with metastatic castration-resistant prostatecancer (CRPC). In vivo, Abiraterone acetate is converted to Abiraterone.In clinical studies, Abiraterone acetate plasma concentrations werebelow detectable levels (<0.2 ng/mL) in >99% of the analyzed samples.

Following oral administration of Abiraterone acetate to patients withmetastatic CRPC, the median time to reach maximum plasma Abirateroneconcentrations is 2 hours. Abiraterone accumulation is observed atsteady-state, with a 2-fold higher exposure (steady-state AUC) comparedto a single 1,000 mg dose of Abiraterone acetate.

At the dose of 1,000 mg daily in patients with metastatic CRPC,steady-state values (mean±SD) of C_(max) were 226±178 ng/mL and of AUCwere 993±639 ng*hr/mL. No major deviation from dose proportionality wasobserved in the dose range of 250 mg to 1,000 mg. However, the exposurewas not significantly increased when the dose was doubled from 1,000 to2,000 mg (8% increase in the mean AUC).

Systemic exposure of Abiraterone is increased when Abiraterone acetateis administered with food. Abiraterone C_(max) and AUC_(0-∞) wereapproximately 7- and 5-fold higher, respectively, when Abirateroneacetate was administered with a low-fat meal (7% fat, 300 calories) andapproximately 17- and 10-fold higher, respectively, when Abirateroneacetate was administered with a high-fat (57% fat, 825 calories) meal.Given the normal variation in the content and composition of meals,taking Zytiga® with meals has the potential to result in increased andhighly variable exposures. Therefore, no food should be consumed for atleast two hours before the dose of Zytiga® is taken and for at least onehour after the dose of Zytiga® is taken. The tablets should be swallowedwhole with water.

Abiraterone is highly bound (>99%) to the human plasma proteins, albuminand alpha-1 acid glycoprotein. The apparent steady-state volume ofdistribution (mean±SD) is 19,669±13,358 L. In vitro studies show that atclinically relevant concentrations, Abiraterone acetate and Abirateroneare not substrates of P-glycoprotein (P-gp) and that Abiraterone acetateis an inhibitor of P-gp. No studies have been conducted with othertransporter proteins.

Following oral administration of ¹⁴C-abiraterone acetate as capsules,Abiraterone acetate is hydrolyzed to Abiraterone (active metabolite).The conversion is likely through esterase activity (the esterases havenot been identified) and is not CYP mediated. The two main circulatingmetabolites of Abiraterone in human plasma are Abiraterone sulphate(inactive) and N-oxide Abiraterone sulphate (inactive), which accountfor about 43% of exposure each. CYP3A4 and SULT2A1 are the enzymesinvolved in the formation of N-oxide Abiraterone sulphate and SULT2A1 isinvolved in the formation of Abiraterone sulphate.

In patients with metastatic CRPC, the mean terminal half-life ofAbiraterone in plasma (mean±SD) is 12±5 hours. Following oraladministration of ¹⁴C-abiraterone acetate, approximately 88% of theradioactive dose is recovered in feces and approximately 5% in urine.The major compounds present in feces are unchanged Abiraterone acetateand Abiraterone (approximately 55% and 22% of the administered dose,respectively).

The usual dose is 4 tablets (1,000 mg) taken together once a day. Thetablets have to be swallowed with a glass of water on an empty stomach.The tablets have to be taken at least one hour before food, or at least2 hours afterwards. Abiraterone has to be taken with a steroid calledprednisolone to help reduce some of the side effects.

In clinical studies following the oral administration of Abirateroneacetate Abiraterone exhibited variable pharmacokinetics and anexceptionally large positive food effect. Abiraterone C_(max) andAUC_(0-∞) (exposure) were increased up to 17- and 10-fold higher,respectively, when a single dose of Abiraterone acetate wasadministered. In order to control Abiraterone plasma concentrationsZytiga® must be taken on an empty stomach. No food should be consumedfor at least two hours before the dose of Zytiga® is taken and for atleast one hour after the dose of Zytiga® is taken. The administered doseis also very large with 1 g taken once daily. Improving the oralbioavailability of the compound in the fasted state would thereforedeliver two advantages: the abandoning of the requirement of taking thedrug on an empty stomach and significant dose reduction. Based on theextent of the food effect of the currently used formula totalelimination of it would allow 10-fold reduction of the dose.

In order to overcome the problems associated with prior conventionalAbiraterone acetate formulations and available drug delivery systemsnovel complex formula of Abiraterone acetate and complexing agents andpharmaceutically acceptable excipients characterized by increasedapparent solubility, instantaneous dissolution, reduced food effectwhich allows significant dose reduction and the abandoning of therequirement of taking the drug on an empty stomach.

A variety of strategies have been used to attempt to overcome theseissues, see for example CN101768199A, CN102558275A, WO2014083512A1,WO2014145813A1, CN102321142A, WO2014102833A2, WO2014009436A1,WO2014145813A1, WO2014009434A1, WO2009009132A1, WO2013164473A1,WO1995011914A1, CA2513746A1, WO2010078300A1, WO2014100418A2 andWO2014009437A1.

DESCRIPTION OF THE INVENTION

The present disclosure relates to a stable complex comprising as activecompound Abiraterone acetate or a combination of active compoundsincluding Abiraterone acetate; and at least one complexing agent.

We have found that only the selected combinations of complexing agentsand, optionally, pharmaceutically acceptable excipients disclosed in thepresent disclosure result in a stable complex formulae having improvedphysicochemical characteristics and enhanced biological performance.

The complexing agents themselves or together with the pharmaceuticallyaccepted excipients have the function to form a complex structure withan active pharmaceutical ingredient through non-covalent secondaryinteractions. The secondary interactions can form through electrostaticinteractions such as ionic interactions, H-bonding, dipole-dipoleinteractions, dipole-induced dipole interactions, London dispersionforces, π-π interactions, and hydrophobic interactions. The complexingagents, pharmaceutically accepted excipients and active ingredients areselected from the group of complexing agents, pharmaceutically acceptedexcipients and active ingredients which are able to form such complexstructures through non-covalent secondary interactions.

In an embodiment, said complexing agent is chosen from polyethyleneglycol glycerides composed of mono-, di- and triglycerides and mono- anddiesters of polyethylene glycol, hydroxypropylcellulose, poloxamers,vinylpyrrolidone/vinyl acetate copolymer, polyethylene glycol,poly(2-ethyl-2-oxazoline), polyvinylpyrrolidone, block copolymers basedon ethylene oxide and propylene oxide, poly(maleic acid/methyl vinylether), polyvinyl caprolactam-polyvinyl acetate-polyethylene glycolgraft copolymer, polyoxyl 15 hydroxystearate, ethylene oxide/propyleneoxide block copolymer, polyvinyl alcohol-polyethylene glycol graftcopolymer, d-alpha tocopheryl polyethylene glycol 1000 succinate andcaprylic/capric triglycerides.

In an embodiment, said complexing agent is chosen frompolyvinylcaprolactam-polyvinyl acetate-polyethylene-glycol graftcopolymers; poloxamers; polyvinylpyrrolidone; copolymers ofvinylpyrrolidone and vinyl-acetate; and poly(maleicacid-co-methyl-vinyl-ether).

In an embodiment, said complexing agent is a polyvinylcaprolactam-polyvinyl acetate-polyethylene glycol graft copolymer.

In an embodiment, said polyvinyl caprolactam-polyvinylacetate-polyethylene glycol graft copolymer is Soluplus having anaverage molecular weight in the range of 90,000-140,000 g/mol, havingthe following structure

In an embodiment, said complex further comprises a pharmaceuticallyacceptable excipient.

In an embodiment, said pharmaceutically acceptable excipient is chosenfrom pharmaceutically acceptable nonionic, anionic, cationic, ionicpolymers, and surfactants.

In an embodiment, said excipient is selected from the group of sodiumlaury sulfate, poloxamer, sodium acetate, citric acid and sodiumdeoxycholate (SDC).

In an embodiment, said excipient is sodium deoxycholate (SDC).

In some embodiments, the compositions may additionally include one ormore pharmaceutically acceptable excipients, auxiliary materials,carriers, active agents or combinations thereof.

In an embodiment, said complex has a particle size less than 600 nm.

In an embodiment said complex has a particle size in the range between50 nm and 600 nm.

In an embodiment said complex has a particle size in the range between100 nm and 500 nm.

In an embodiment, said complex is instantaneously redispersible inphysiological relevant media.

In an embodiment, said complex has increased dissolution rate comparedto the commercially available form of Abiraterone acetate (Zytiga).

In an embodiment, said complex is stable in solid form and in colloidsolution and/or dispersion.

In an embodiment, said complex's apparent solubility in water is atleast 0.6 mg/mL.

In an embodiment, said complex exhibits X-ray amorphous character in thesolid form.

In an embodiment, said complex has a PAMPA permeability of at least0.5*10⁻⁶ cm/s when dispersed in distilled water, which does not decreasein time at least for 3 months.

In an embodiment, said complex exhibits no positive food effect whichallows significant dose reduction and the abandoning of the requirementof taking the drug on an empty stomach.

In an embodiment, said complex exhibits no positive food effect based onin-vivo dog and clinical studies.

In an embodiment, the variability of exposure of the complex issignificantly reduced compared to the commercially available form(Zytiga).

In an embodiment said complex comprises

-   -   a) Abiraterone acetate; or a combination of active compounds        including Abiraterone acetate;    -   b) polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol        graft copolymer as a complexing agent; and    -   c) sodium deoxycholate as an excipient.

In an embodiment said complex comprises 5 to 40% by weight ofAbiraterone acetate.

In an embodiment said complex comprises 5 to 80% by weight of apolyvinylcaprolactam-polyvinyl acetate-polyethylene-glycol graftcopolymer.

In an embodiment, said complex comprises 0.1 to 50% by weight of sodiumdeoxycholate.

In an embodiment said complex comprises

-   -   a) 5 to 40% by weight of Abiraterone acetate;    -   b) 5 to 80% by weight of a polyvinylcaprolactam-polyvinyl        acetate-polyethylene-glycol graft copolymer; and    -   c) 0.1 to 50% by weight of sodium deoxycholate.

In an embodiment, said complex further comprises an additional activeagent chosen from agents useful in the treatment of early stage andmetastatic prostate cancer and advanced breast cancer.

In an embodiment, said complex further comprises one or more additionalactive agents selected from Rifampicin, Prednisone/Prednisolone,Dexamethasone, Ketoconazole, Testosterone Enanthate, Enzalutamide,Dextromethorphan hydrobromide, Dexamethasone, Exemestane, Goserelin,Degarelix, Veliparib, Dovitinib, Leuprolide, Alisertib, cabozantinib,Cabazitaxel, Dasatinib, Glucocorticoid, Docetaxel, Dutasteride,Hydroxychloroquine, Ipilimumab, Metformin, Sunitinib, Selinexor,Everolimus, Trastuzumab, Tamoxifen, and combinations thereof.

In an embodiment, said complex is characterized by infrared (ATR)spectrum having main/characteristic absorption peaks at least at 569cm⁻¹, 607 cm⁻¹, 713 cm⁻¹, 797 cm⁻¹, 843 cm⁻¹, 942 cm⁻¹, 973 cm⁻¹, 1030cm⁻¹, 1103 cm⁻¹, 1148 cm⁻¹, 1195 cm⁻¹, 1241 cm⁻¹, 1333 cm⁻¹, 1371 cm⁻¹,1421 cm⁻¹, 1441 cm⁻¹, 1477 cm⁻¹, 1336 cm⁻¹, 1734 cm⁻¹, 2858 cm⁻¹, 2928cm⁻¹ characteristic absorption peaks.

In an embodiment, said complex is characterized by Raman spectrum havingmain/characteristic absorption peaks at least at 239 cm⁻¹, 581 cm⁻¹, 701cm⁻¹, 797 cm⁻¹, 846 cm⁻¹, 1026 cm⁻¹, 1088 cm⁻¹, 1196 cm⁻¹, 1264 cm⁻¹,1445 cm⁻¹, 1584 cm⁻¹, 1600 cm⁻¹, 1735 cm⁻¹ characteristic absorptionpeaks.

Disclosed herein is a process for the preparation of a stable complex ofAbiraterone acetate, said process comprising the step of mixing asolution of the active agent and at least one complexing agent andoptionally one or more pharmaceutically acceptable excipient in apharmaceutically acceptable solvent with an aqueous solution containingoptionally least one pharmaceutically acceptable excipient.

In an embodiment said complex is obtained via a mixing process.

In an embodiment said complex is obtained via a continuous flow mixingprocess.

In an embodiment said process is performed in a continuous flowinstrument.

In an embodiment said continuous flow instrument is a microfluidic flowinstrument.

In an embodiment, said complex is not obtained via a milling process, byhigh pressure homogenization process, encapsulation process or soliddispersion process.

In an embodiment said pharmaceutically acceptable solvent is chosen fromwater, methanol, ethanol, isopropanol, n-propanol, acetone,acetonitrile, dimethyl-sulfoxide, tetrahydrofuran, or combinationsthereof.

In an embodiment, said pharmaceutically acceptable solvent is acombination of water and tetrahydrofuran.

In an embodiment said solvents are miscible with each other and theaqueous solvent comprises 0.1 to 99.9% weight of the final solution.

In an embodiment, said aqueous solvent comprises 0.1 to 99.9% weight ofthe final solution.

In an embodiment, said aqueous solvent comprises 50 to 90% weight of thefinal solution.

In an embodiment, said aqueous solvent comprises 50 to 80% weight of thefinal solution.

In an embodiment, said aqueous solvent comprises 50 to 70% weight of thefinal solution.

In an embodiment, said aqueous solvent comprises 50 to 60% weight of thefinal solution.

In an embodiment, said aqueous solvent comprises 50% weight of the finalsolution.

In an embodiment, said aqueous solvent comprises 10 to 40% weight of thefinal solution.

In an embodiment, said aqueous solvent comprises 10 to 30% weight of thefinal solution.

In an embodiment, said aqueous solvent comprises 10 to 20% weight of thefinal solution.

In an embodiment, said aqueous solvent comprises 10% weight of the finalsolution.

In an embodiment said complex further comprises a pharmaceuticallyacceptable carrier.

In an embodiment said composition is suitable for oral, pulmonary,rectal, colonic, parenteral, intracisternal, intravaginal,intraperitoneal, ocular, otic, local, buccal, nasal, or topicaladministration.

In an embodiment said composition is suitable for oral administration.

Disclosed herein is a complex for use in the manufacture of a medicamentfor the treatment of prostate cancer and advanced breast cancer.

Disclosed herein is a complex for use for the treatment of prostatecancer and advanced breast cancer.

In an embodiment, a method for reducing the therapeutically effectivedosage of Abiraterone acetate compared to Zytiga® tablets comprises oraladministration of a pharmaceutical composition as described herein.

The present disclosure relates to a stable complex comprising as activecompound Abiraterone acetate or a combination of active compoundsincluding Abiraterone acetate; and at least one complexing agent chosenfrom polyvinylcaprolactam-polyvinyl acetate-polyethylene-glycol graftcopolymers; poloxamers; polyvinylpyrrolidone; copolymers ofvinylpyrrolidone and vinyl-acetate; and poly(maleicacid-co-methyl-vinyl-ether); said complex characterized in that it has aparticle size less than 600 nm and possesses at least one of thefollowing properties:

-   -   a) is instantaneously redispersible in physiological relevant        media;    -   b) has increased dissolution rate compared to the commercially        available form of Abiraterone acetate (Zytiga);    -   c) is stable in solid form and in colloid solution and/or        dispersion;    -   d) apparent solubility in water of at least 0.6 mg/mL;    -   e) has a PAMPA permeability of at least 0.5*10⁻⁶ cm/s when        dispersed in distilled water, which does not decrease in time at        least for 3 months;    -   f) exhibits no positive food effect which allows significant        dose reduction and the abandoning of the requirement of taking        the drug on an empty stomach; and    -   g) the variability of exposure of the complex is significantly        reduced compared to the commercially available form (Zytiga).

In an embodiment, said complex possesses at least two of the propertiesdescribed in a)-g).

In an embodiment, said complex possesses at least three of theproperties described in a)-g).

In an embodiment, said complex has an apparent solubility in water of atleast 0.6 mg/mL and exhibits no positive food effect which allowssignificant dose reduction and the abandoning of the requirement oftaking the drug on an empty stomach.

In an embodiment, said complex has a PAMPA permeability of at least0.5*10⁻⁶ cm/s and exhibits no positive food effect which allowssignificant dose reduction and the abandoning of the requirement oftaking the drug on an empty stomach.

In an embodiment, said complex has an apparent solubility in water of atleast 0.6 mg/mL and a PAMPA permeability of at least 0.5*10⁻⁶ cm/s.

In an embodiment, said complex has an apparent solubility in water of atleast 0.6 mg/mL, PAMPA permeability of at least 0.5*10⁻⁶ cm/s andexhibits no positive food effect which allows significant dose reductionand the abandoning of the requirement of taking the drug on an emptystomach.

In an embodiment, said complexing agent which is apolyvinylcaprolactam-polyvinyl acetate-polyethylene-glycol graftcopolymer and pharmaceutically acceptable excipient which is sodiumdeoxycholate comprise 10 weight % to about 95 weight % of the totalweight of the complex.

In another aspect the complexing agents and/or pharmaceuticallyacceptable excipients are associated or interact with the Abirateroneacetate as the result of the mixing process. In an embodiment, saidmixing process is a continuous flow mixing process.

In some embodiments, the structure of the complex Abiraterone acetateformula is different from the core-shell type milled particle,precipitated encapsulated particles, micelles and solid dispersions.

The pharmaceutical composition of the disclosure can be formulated: (a)for administration selected from the group consisting of oral,pulmonary, rectal, colonic, parenteral, intracisternal, intravaginal,intraperitoneal, ocular, otic, local, buccal, nasal, and topicaladministration; (b) into a dosage form selected from the groupconsisting of liquid dispersions, gels, aerosols, ointments, creams,lyophilized formulations, tablets, capsules; (c) into a dosage formselected from the group consisting of controlled release formulations,fast melt formulations, delayed release formulations, extended releaseformulations, pulsatile release formulations, and mixed immediaterelease and controlled release formulations; or (d) any combination of(a), (b), and (c).

In an embodiment, said compositions can be formulated by addingdifferent types of pharmaceutically acceptable excipients for oraladministration in solid, liquid, local (powders, ointments or drops), ortopical administration, and the like.

In an embodiment, said dosage form is a solid dosage form.

Solid dosage forms for oral administration include, but are not limitedto, capsules, tablets, pills, powders, and granules. In such soliddosage forms, the active agent is admixed with at least one of thefollowing excipients: (a) one or more inert excipients (or carriers),such as sodium citrate or dicalcium phosphate; (b) fillers or extenders,such as starches, lactose, sucrose, glucose, mannitol, microcrystallinecellulose and silicic acid; (c) binders, such as cellulose derivatives,alginates, gelatin, polyvinylpyrrolidone, sucrose and acacia; (d)humectants, such as glycerol; (e) disintegrating agents, such ascrospovidon, sodium starch glycolate, effervescent compositions,croscarmellose sodium, calcium carbonate, potato or tapioca starch,alginic acid, certain complex silicates and sodium carbonate; (f)solution retarders, such as acrylates, cellulose derivatives, paraffin;(g) absorption accelerators, such as quaternary ammonium compounds; (h)wetting agents, such as polysorbates, cetyl alcohol and glycerolmonostearate; (i) adsorbents, such as kaolin and bentonite; and (j)lubricants, such as talc, calcium stearate, magnesium stearate, solidpolyethylene glycols, sodium lauryl sulfate, or mixtures thereof. Forcapsules, tablets, and pills, the dosage forms may also comprisebuffering agents.

Besides such inert diluents, the composition can also include adjuvants,such as wetting agents, emulsifying and suspending agents, sweetening,flavoring, and perfuming agents.

Advantages of the complex Abiraterone acetate formulae of the disclosureinclude, but are not limited to (1) physical and chemical stability, (2)instantaneous redispersibility, (3) stability in colloid solution ordispersion in the therapeutic time window, (4) increased apparentsolubility compared to the conventional Abiraterone acetate formulation(Zytiga), (5) increased permeability, (6) increased oral bioavailabilityin fasted state, and (7) no positive food effect.

In an embodiment, solid form of said complex has good processability forthe preparation of any type of pharmaceutical dosage form.

In an embodiment, said complex has good/instantaneous redispersibilityof solid complex formulae of Abiraterone acetate in water, biologicallyrelevant media, e.g. SGF, FessiF and FassiF media and gastro intestinalfluids and adequate stability in colloid solutions and/or dispersion inthe therapeutic time window.

In an embodiment, said complex has increased apparent solubility andpermeability compared to the commercially available dosage form(Zytiga). In some embodiments, the apparent solubility and permeabilityof the complex Abiraterone acetate formulae is at least 0.6 mg/mL and0.5*10⁻⁶ cm/s, respectively.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the complexing agent screening for formula selection inorder to select the formulae having instantaneous redispersibility.

FIG. 2 shows comparative PAMPA assays of complex Abiraterone acetateformulations consisting of different pharmaceutically acceptableexcipients.

FIG. 3 shows comparative PAMPA assays of complex Abiraterone acetateformulations containing complexing agent and pharmaceutically acceptableexcipient in different ratios.

FIG. 4. shows the stability of the redispersed complex Abirateroneacetate formulation prepared with different flow rate ratios.

FIG. 5 shows the particle size distribution of the as-synthetizedcolloid solution and redispersed solid complex of the selected formula.

FIG. 6. shows stability of the redispersed complex Abiraterone acetateformulation prepared with intensified process flow rates.

FIG. 7 shows the effect of the production temperature on the Abirateroneacetate content of the filtrate of the redispersed Complex Abirateroneacetate formulation.

FIG. 8 shows dissolution profile of wet milled Abiraterone acetate andcomplex Abiraterone acetate in FaSSIF medium.

FIG. 9 shows dissolution profile of wet milled Abiraterone acetate andcomplex Abiraterone acetate in FeSSIF medium.

FIG. 10 shows PAMPA permeability of extruded Abiraterone acetateformulation and complex Abiraterone formulation of the presentdisclosure.

FIG. 11 shows the stability of the colloid solution in simulated fastedand fed state.

FIG. 12 shows dissolution profile of crystalline Abiraterone acetate,physical mixture, Zytiga and complex Abiraterone acetate in FaSSIFmedium.

FIG. 13 shows dissolution profile of crystalline Abiraterone acetate,physical mixture, Zytiga and complex Abiraterone acetate in FeSSIFmedium.

FIG. 14 shows the stability of the solid form detected as the PAMPApermeability measured after redispersion in distilled water afterstorage at different conditions.

FIG. 15 shows scanning electron microscope (SEM) images about thecomplexes of Abiraterone acetate according to the present disclosure (B:the complex of the present disclosure containing Abiraterone acetate,polyvinylcaprolactam-polyvinyl acetate-polyethylene-glycol graftcopolymer (Soluplus) and sodium deoxycholate; D: the complex of thepresent disclosure containing Abiraterone acetate,polyvinylcaprolactam-polyvinyl acetate-polyethylene-glycol graftcopolymer (Soluplus), caprylic/capric triglyceride (Miglyol 812 N) andsodium deoxycholate and poloxamer (poloxamer 407)) and the placebosamples prepared in the absence of Abiraterone acetate (A and C).

FIG. 16 shows ATR spectra of crystalline Abiraterone acetate (A),complex Abiraterone acetate (B), placebo sample (C),polyvinylcaprolactam-polyvinyl acetate-polyethylene-glycol graftcopolymer (Soluplus) (D) and sodium deoxycholate (E)

FIG. 17 shows Raman spectra of crystalline Abiraterone acetate (A),complex Abiraterone acetate (B), placebo sample (C),polyvinylcaprolactam-polyvinyl acetate-polyethylene-glycol graftcopolymer (Soluplus) (D) and sodium deoxycholate (E)

FIG. 18 shows powder X-ray diffractograms of crystalline Abirateroneacetate, place sample and complex Abiraterone acetate formulation.

FIG. 19 shows the plasma Abiraterone concentrations following the oraladministration of 50 mg Zytiga (A) and Complex Abiraterone acetate (B)according to the disclosure to beagle dogs (11-13 kg, n=4) in the fastedand in the fed conditions.

FIG. 20 shows plasma concentration of Abiraterone following the oraladministration of 200 mg Complex Abiraterone acetate formula to 10healthy male volunteers in the fasted and in the fed state.

EXAMPLES

Several pharmaceutically acceptable complexing agents andpharmaceutically acceptable excipients and their combinations weretested in order to select the formulae having instantaneousredispersibility as shown in FIG. 1. One of the examples that displayedan acceptable level of redispersibility was selected for furtheranalysis.

PAMPA permeability of the selected formulations was measured in order toselect the complex Abiraterone acetate formulation having the bestin-vitro performance (FIG. 2). PAMPA permeability measurements wereperformed as described by M Kansi et al. (Journal of medicinalchemistry, 41, (1998) pp 1007) with modifications based on S. Bendels etal (Pharmaceutical research, 23 (2006) pp 2525). Permeability wasmeasured in a 96-well plate assay across an artificial membrane composedof dodecane with 20% soy lecithin supported by a PVDF membrane(Millipore, USA). The receiver compartment was phosphate buffered saline(pH 7.0) supplemented with 1% sodium dodecyl sulfate. The assay wasperformed at room temperature; incubation time was 1-24 hours. Theconcentration in the receiver compartment was determined by UV-VISspectrophotometry (Thermo Scientific Genesys S10).

Polyvinylcaprolactam-polyvinyl acetate-polyethylene-glycol graftcopolymer (Soluplus) as complexing agent and sodium deoxycholate (SDC)as pharmaceutically accepted excipient were selected to form complexAbiraterone acetate formulation having improved materialcharacteristics. Based on the in-vitro properties (redispersibilityprofile, stability of the redispersed solution and PAMPA permeability)(Table 1 and FIG. 3) the optimal ratio of Abiraterone acetate,polyvinylcaprolactam-polyvinyl acetate-polyethylene-glycol graftcopolymer (Soluplus) and sodium deoxycholate (SDC) in the complexformulation of the present disclosure was found to be 1:4:0.6.

TABLE 1 shows comparative PAMPA assays of complex Abiraterone acetateformulations containing different amount of Soluplus and SDC indifferent ratios SDC ratio to Abiraterone Soluplus ratio to Abirateroneacetate acetate 2X 3X 4X Redispersibility and stability 0.2X notdispersable dispersable, unstable dispersable, unstable 0.6X notdispersable dispersable, stable dispersable, stable 1X dispersable,dispersable, stable dispersable, stable unstable PAMPA permeability(10⁻⁶ cm/s) 0.2X 0.504 0.584 0.784 0.6X 0.665 0.699 0.677 1X 0.629 0.604—

The technological approach applied to the manufacture powder of thecomplex Abiraterone acetate formulation of the present invention reliedon freeze-drying or spray-drying of the colloid solution of complexAbiraterone acetate formulation containing selected complexationagent(s), pharmaceutically acceptable excipient(s) and the active drugsubstance. The colloid solution of complex Abiraterone acetateformulation of the present invention was prepared by continuous flowmixing of two solutions. One of the solutions contained the Abirateroneacetate and the complexation agent(s). The second solution was water andcontains the pharmaceutically acceptable excipient(s). The colloidsolution was solidified right after the preparation. Properties of theproduced colloid solution could be modified during the process byprecise control and optimization of various transformation parameters(e.g. temperature, flow rate and concentration).

Colloid solutions of Abiraterone acetate complex formulation of thepresent disclosure were prepared by continuous mixing process usingSolution 1/a,b,c containing Abiraterone acetate and Soluplus® andSolution 2/a,b,c containing sodium deoxycholate (SDC) as shown in 2. Theoptimized Abiraterone acetate: excipients ratio of the complexAbiraterone acetate formulation (1:4:0.6) was kept constant. Differentflow rate ratios were tested in order to determine the optimalmanufacturing condition. The total flow rate of the production (sum ofthe Solvent 1 and Solvent 2 flow rates) and the amount of the colloidsolution collected were kept constant at 50.0 mL/min and 25.0 mL,respectively. The appearance of the produced colloid solution and thestability of the redispersed complex Abiraterone acetate formulationswere used to determine the optimal parameters of the production. Table 3summarizes the results.

TABLE 2 shows the composition of the solution used for the production ofthe colloid solutions of Abiraterone acetate complex formulation of thepresent disclosure. Solvent Concentration of Components Solution 1/aTetrahydrofuran Abiraterone acetate Soluplus ® 10 mg/mL 40 mg/mLSolution 1/b Tetrahydrofuran Abiraterone acetate Soluplus ® 20 mg/mL 80mg/mL Solution 1/c Tetrahydrofuran Abiraterone acetate Soluplus ® 40mg/mL 160 mg/mL Solution 2/a purified water Sodium — deoxycholate 1.500mg/mL Solution 2/b purified water Sodium — deoxycholate 1.340 mg/mLSolution 2/c purified water Sodium — deoxycholate 1.260 mg/mL

TABLE 3 shows effect of the flow rate ratio on the appearance andstability of the redispersed formulae. Appearance of redispersedSolution 1 Solution 2 Solvent 1:Solvent 2 ratio formulation Solution 1/aSolution 2/a 1:4 milky solution Solution 1/b Solution 2/b 1:9 milkysolution Solution 1/c Solution 2/c  1:19 milky solution

The stability of the redispersed freeze-dried samples was monitored.Solid formulations of complex Abiraterone acetate were redispersed inpurified water or in biorelevant media using 1 mg/mL concentration forthe Abiraterone acetate. The stability of redispersed formulations wasmonitored by filtering it with 0.45 μm pore size filter at differenttime points. The Abiraterone acetate contents of the filtrates weredetermined by UV-VIS spectrophotometry (VWR UV-3100 PC) (FIG. 4). Flowrate ratio of 1:4 was found to be optimal for the production of complexAbiraterone acetate formulation of the present disclosure.

A colloid solution of Abiraterone acetate complex formula(Formulation 1) with the optimal ratio of the complexing agent andpharmaceutically acceptable excipient of the present disclosure wasprepared by continuous flow mixing in a flow instrument. As a startingsolution, 1000 mg Abiraterone acetate and 4000 mgpolyvinylcaprolactam-polyvinyl acetate-polyethylene-glycol graftcopolymer (Soluplus) dissolved in 100 mL tetrahydrofuran was used. Theprepared solution was passed into the instrument with 10 mL/min flowrate. Meanwhile, aqueous solvent containing 750 mg sodium deoxycholatein 500 mL water was passed into the instrument with 40 mL/min flow rate,where Abiraterone acetate formed complex Abiraterone acetatecomposition. The colloid solution of the complex Abiraterone acetate iscontinuously produced at atmospheric pressure. The produced colloidsolution was frozen on dry-ice and then it was lyophilized using afreeze drier equipped with −110° C. ice condenser, with a vacuum pump.For the process monitoring particle size and size distribution of thecomplex Abiraterone acetate formula was used. Particle size and sizedistribution of the colloid solution right after the production and thereconstituted solid complex Abiraterone acetate formula are seen inError! Reference source not found. It was found to be D(50)=310 nm forthe produced colloid solution and D(50)=158 nm for the redispersedparticles, respectively (FIG. 5).

Process intensification was performed in order to increase theefficiency of the production. The flow rate ratio was increased from 1:4to 10:40. The produced colloid solution of the complex Abirateroneacetate formulation of the present disclosure was solid formulated usingfreeze-drying method as described above. The samples were reconstitutedusing purified water. The physical stability of redispersed solution wasalso monitored in time by the determination of the Abiraterone acetatecontent of the redispersed solution after filtration (FIG. 6). Processintensification did not have effect on the stability of the redispersedsolution.

With 5:20 flow rate ratio, solvent mixture containing novel Abirateroneacetate complex formulation (Formulation 1) was prepared and solidformulated using freeze-drying method. The stability of the freeze-driedpowder was tested after one week storage at 4° C. The samples werereconstituted using purified water. The results showed that theAbiraterone acetate content of the filtrate right after the productionwas identical to Abiraterone acetate content of the filtrate after oneweek storage within the experimental accuracy. The Abiraterone acetatecontent of the filtrates slightly decreases in time; however it does nothave effect on the appearance and redispersibility of the freeze-driedpowder.

The effect of the production temperature on the product quality wasinvestigated. Colloid solution of complex Abiraterone acetateformulation of the present disclosure was prepared using the intensifiedand optimized parameter sets described above at 20-, 30- and 40° C.temperatures. The colloid solutions produced were then freeze-dried. Thefreeze-dried samples were redispersed in purified water and theirstability was monitored in time as previously described (FIG. 7).Optimal production temperature was found to be 30° C.

Comparative Formulation Studies

Crystalline Abiraterone acetate was wet milled in the presence ofpolyvinyl caprolactam-polyvinyl acetate-polyethylene glycol graftcopolymer (Soluplus) and Sodium deoxycholate in order to producenanosized Abiraterone acetate particles. The milling process was carriedout using a Fritsch Pulverisette 6 instrument. Volume of Si2N3 millingvessel was 250 mL. 25 milling balls with 10 mm diameter was used.Milling speed was set to be 500 rpm. 5×1 h milling time was applied.

Milled suspension contained 0.447 g Abiraterone acetate, 1.178 gSoluplus and 0.267 g Sodium deoxycholate in 12.5 mL MilliQ water. Thewet milling process resulted in a foam-like suspension which wasfreeze-dried to obtain solid powder.

Dissolution profile of wet milled Abiraterone was compared with thedissolution of crystalline Abiraterone acetate and complex Abirateroneacetate of the present disclosure at 37° C. 10 mg Abiraterone acetateequivalent samples were dispersed in 20 mL FaSSIF (fasted) and FeSSIF(fed) media and were filtered by 20 nm disposable syringe filter. Theactive content in the filtrate was measured by UV-Vis spectrophotometry.

Abiraterone acetate dissolution from the complex Abiraterone acetateformulation of the present disclosure is 3-fold higher in FeSSIF and9-fold higher in FaSSIF compared to the dissolved amount of Abirateroneacetate from the wet milled samples (FIG. 8 and FIG. 9). Pharmaceuticalformulation of Abiraterone acetate was prepared by extrusion techniqueusing polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol graftcopolymer (Soluplus) and Sodium deoxycholate as pharmaceuticallyacceptable excipients. The extrusion was carried out using HAAKE™MiniLab II Micro Compounder (Thermo Scientific) instrument. In apremixing step, dry powders (17.9 w/w % Abireterone-acetate, 71.4 w/w %Soluplus, 10.7 w/w % SDC) were mixed in a mortar then 8 g powder mixturewas fed into the extruder. The extrusion was performed at 130° C. with ascrew rate of 20 rpm. PAMPA permeability of the extruded Abirateroneacetate formulation was compared to the PAMPA permeability of complexAbiraterone acetate formulation of the present disclosure in water,FaSSIF and FeSSIF media. PAMPA permeability of complex Abirateroneacetate was 2-fold higher in FeSSIF medium than the permeability of theextruded formulation (FIG. 10).

Comparative Solubility Tests

The apparent solubility of complex Abiraterone acetate formula andunformulated compounds was measured by UV-VIS spectroscopy at roomtemperature. The samples were dispersed in distillated water and theresulting dispersions were filtered by 100 nm disposable syringe filter.The active content in the filtrate was measured by UV-Visspectrophotometry and the solubility was calculated. The filtrate maycontain Abiraterone acetate complex particles which could not befiltrated out using 100 nm pore size filter.

Solubility of complex Abiraterone acetate formula and unformulatedcompound was 0.6 mg/mL and <0.004 mg/mL, respectively.

Comparative In-Vitro PAMPA Assays

PAMPA permeability of complex Abiraterone acetate formula was above0.5*10⁻⁶ cm/s, while it was below 0.1*10⁻⁶ cm/s for the unformulatedcompound.

Stability of the Colloid Solution in the GI Tract

A simulated passage through the GI tract was performed in order todetect any instability of the colloid solution at pH values and bileacid concentrations representative of the GI tract in the fasted and inthe fed conditions. No significant change in light scattering of thecolloid solution was observed in the simulation indicating that thecomplex Abiraterone formula will be stable under these conditions in thetime window of the absorption process in both the fasted and in the fedconditions (FIG. 11 Error! Reference source not found.).

Comparative Dissolution Tests

Dissolution of crystalline Abiraterone acetate, physical mixture of thecomposition of the present disclosure, wet milled composition of thepresent disclosure and complex Abiraterone acetate formulation of thepresent disclosure was measured by UV-VIS spectroscopy at 37° C. 10 mgAbiraterone acetate equivalent samples were dispersed in 20 mL FaSSIFand FeSSIF media and were filtered by 100 nm (crystalline Abirateroneacetate, Zytiga and the physical mixture) or a 20 nm (Abirateronecomplex) disposable syringe filter. The active content in the filtratewas measured by UV-Vis spectrophotometry (FIG. 12 and FIG. 13).

Stability of the Solid Form

PAMPA permeability of the solid complex is measured after storage atdifferent conditions. 3 month storage at 4° C., RT or 40° C. 75%relative humidity showed no significant decrease in the measured PAMPApermeability under any of the conditions tested (FIG. 14).

Structural Analysis

Morphology of complex Abiraterone acetate formulation was investigatedusing FEI Quanta 3D scanning electron microscope. The morphology of thecomplex of the present disclosure was compared to the placebo samples(prepared in the absence of Abiraterone acetate), prepared as describedabove. Complexes of Abiraterone acetate of the present disclosureconsists of spherical particles (FIG. 15 B). In the lack of the activecompound, the complexing agent(s) and pharmaceutically acceptableexcipient(s) do not form spherical particles (FIG. 15A).

Structural analysis was performed by using Bruker Vertex 70 FT-IRspectrometer with Bruker Platinum diamond ATR unit and HORIBA JobinYvonLabRAM HR UV-VIS-NIR equipped with Olympus BXFM free-space microscopeusing a 785 nm (NIR) diode laser.

In an embodiment, said complex is characterized by infrared (ATR)spectrum having main/characteristic absorption peaks at least at 569cm⁻¹, 607 cm⁻¹, 713 cm⁻¹, 797 cm⁻¹, 843 cm⁻¹, 942 cm⁻¹, 973 cm⁻¹, 1030cm⁻¹, 1103 cm⁻¹, 1148 cm⁻¹, 1195 cm⁻¹, 1241 cm⁻¹, 1333 cm⁻¹, 1371 cm⁻¹,1421 cm⁻¹, 1441 cm⁻¹, 1477 cm⁻¹, 1336 cm⁻¹, 1734 cm⁻¹, 2858 cm⁻¹, 2928cm⁻¹ characteristic absorption peaks (FIG. 16).

In an embodiment, said complex is characterized by infrared (ATR)spectrum having main/characteristic absorption peaks at least at 713cm⁻¹, 1030 cm⁻¹, 1103 cm⁻¹1734 cm⁻ characteristic absorption peaks.

In an embodiment, said complex is further characterized by Ramanspectrum having main/characteristic absorption peaks at 239 cm⁻¹, 581cm⁻¹, 701 cm⁻¹, 797 cm⁻¹, 846 cm⁻¹, 1026 cm⁻¹, 1088 cm⁻¹, 1196 cm⁻¹,1264 cm⁻¹, 1445 cm⁻¹, 1584 cm⁻¹, 1600 cm⁻¹, 1735 cm⁻¹ (FIG. 17).

In an embodiment, said complex is further characterized by Ramanspectrum having main/characteristic absorption peaks at 581 cm⁻¹, 1026cm⁻¹, and 1445 cm⁻¹.

The structure of the complex Abiraterone acetate of the presentdisclosure was investigated by powder X-ray diffraction (XRD) analysis(Philips PW1050/1870 RTG powder-diffractometer). The measurements showedthat the complex Abiraterone acetate composition was XRD amorphous (seein FIG. 18). Characteristic reflections on the diffractogram of complexAbiraterone acetate and placebo sample are be attributed to sampleholder.

Pharmaceutical Formulation

50 mg dose strength powder in a bottle (PIB) formulation of complexAbiraterone acetate of the present disclosure was prepared. Followingproduction parameters were used for the manufacturing process:

-   -   Solvent 1: Tetrahydrofuran    -   C_(Abiraterone acetate): 10 mg/mL    -   C_(Soluplus®): 40 mg/mL    -   Solvent 2: Purified water    -   C_(Sodium deoxycholate): 3.5 mg/mL    -   Flow rate_(Solution 1): 10.0 mL/min    -   Flow rate_(Solution 2): 40.0 mL/min    -   Temperature: 30° C.    -   Filling volume: 25 mL    -   Freezing time: 30 min in dry-ice/Acetone bath at least    -   Freeze-drying time: 36 h at least

Abiraterone acetate content of the produced colloid was investigatedright after the production and after filtration with 0.45 μm pore sizefilter. The active content of the colloid solution was 2.007 mg/mL,while the Abiraterone acetate content of the filtrate was found to be2.026 mg/mL. The nominal active content of the solution mixture is 2.000mg/mL.

Determination of Mass Uniformity of PiB Formulation:

25 mL aliquots of produced solution mixture were filled into 200 mLamber glass pharmaceutical bottles. The weight of the PiB formulationwas checked after the freeze-drying process. The average mass of thefreeze-dried powders in the bottles was 0.2773 mg±0.0015 mg.

Determination of Content Uniformity of PiB Formulation:

Content uniformity of the freeze-dried PiB formulations wasinvestigated. The freeze-dried powder was dissolved in methanol. TheAbiraterone acetate content was measured by HPLC method. Each samplestested met AV NMT 15 criterion.

Determination of Stability of PiB Formulation in Solid and ReconstitutedSolution:

Abiraterone acetate complex PiB formulations were reconstituted with 50mL purified water right after the production and 2 weeks storage at 40°C. The stability of reconstituted colloid solutions were monitored intime determining the active content of the colloid solution afterfiltration with 0.45 μm pore size filter. The Abiraterone acetatecontents of the filtrate were in a good agreement right after theproduction and 2 weeks storage. Both reconstitutions resulted inhomogenous opalescent colloid solutions which were practically free ofvisible particles.

The reconstituted colloid solution was ready for administration within10 minutes. The reconstituted solution was stable for at least 4 hour atroom temperature.

Determination of pH of Reconstituted PiB Formulations:

pH of the reconstituted PiB formulations of complex Abiraterone acetateof the present disclosure was investigated. The pH of each reconstitutedsolution was within the pH range recommended by the ICH guidelines forthe products intended for oral administration (Table 4).

TABLE 4 pH of reconstituted solutions pH Right after the productionReconstitution with 50 mL purified water 7.35 After 2 months storageReconstitution with 50 mL purified water 7.40

Determination of Water Content of FIB Formulation:

Karl Fischer titration was used to determine the water content of thePiB formulations of complex Abiraterone acetate of the presentdisclosure right after the production (Table 5).

TABLE 5 Water content of PiB formulations right after the productionBottle ID Water content (%) Average SD U0161 1.85 U0161 1.74 1.84 0.10U0161 1.93 Measured at RH = 75%

The water content of the formulation met the acceptance criteriaspecified in the relevant ICH guidelines in each case.

Reconstitution and Administration for 50 mg Dose:

Reconstitution of the PiB formulations of complex Abiraterone acetate ofthe present disclosure using 50 mL Ph.Eur water yielded an opalescentsolution within 10 minutes. This solution had to be administered orally.Another 190 mL of Ph.Eur water should be added to the bottle making thetotal of orally administered volume 240 mL.

Reconstitution and Administration for 100 mg Dose:

Reconstitution of the PiB formulations of complex Abiraterone acetate ofthe present disclosure using 50 mL of Ph.Eur water yielded an opalescentsolution. This liquid had to be administered orally. Another 70 mL ofPh.Eur water should be added to the bottle and administered orally. Theadministration should be repeated using a second bottle of 50 mgstrength PiB formulation. The total of orally administered volume willbe 240 mL.

Reconstitution and Administration for 200 mg Dose:

Reconstitution of the PiB formulations of complex Abiraterone acetate ofthe present disclosure using 50 mL of Ph.Eur water yielded an opalescentsolution. This liquid has to be administered orally. Another 10 mL ofPh.Eur water should be added to the bottle and administered orally. Theadministration should be repeated four times using another three bottlesof 50 mg strength PiB formulation. The total of orally administeredvolume will be 240 mL.

The reconstitution of the PiB formulations of the complex Abirateroneacetate of the present disclosure was tested. Different amount of Ph.Eurwater was added to the PiB formulations in order to reconstitute thefreeze-dried powder. The Abiraterone acetate content of thereconstituted colloid solutions was measured. Then the bottles wererinsed once adding 10 mL of Ph.Eur water. The Abiraterone acetatecontent of rising liquid was also measured. Finally the bottles wererinsed with methanol to dissolve completely the remaining Abirateroneacetate. The Abiraterone acetate content was also determined in thiscase (Table 6). More than 98% of the Abiraterone acetate content was inthe reconstituted volume. After 1 rising step less than 0.7% Abirateroneacetate remained in the bottles.

TABLE 6 Abiraterone acetate content of the PIB formulations afterreconstitution c_(Solution) Abiraterone acetate Bottle ID: U0920 (mg/mL)content (mg) V_(Ph.Eur water) = 50 mL 1.0404 52.02 Rinsing withV_(Ph.Eur water) = 10 mL 0.0747 0.75 Rinsing with V_(Methanol) = 10 mL0.0390 0.39 Total 53.16

In-Vivo Pharmacokinetics In-Vivo PK Test in Animals

The administration of 50 mg Zytiga to beagle dogs in the fasted and inthe fed (high fat) state absorption was rapid in both cases, however,plasma concentrations, C_(max) and AUC_(inf) values were over 5-foldlower in the fasted state than in the fed (high fat) state (FIG. 19 A).Following oral administration of the complex Abiraterone acetate formulato fasted and fed (high fat) beagle dogs the maximal plasma Abirateroneconcentrations were detected at 0.5 hour indicating immediate absorptionof the Abiraterone acetate from the Complex Abiraterone acetateformulation of the present disclosure. No significant differences wereobserved in the plasma concentrations when the compound was administeredin the fasted or in the fed (high fat) state (FIG. 19 B). AUC_(inf) andC_(max) values calculated from the curves showed significantly higherexposure for the Complex Abiraterone acetate formula than for Zytigaboth in the fasted and in the fed state along with total elimination ofthe positive food effect Zytiga exhibits (Table 7).

Feeding AUC_(last) Test article condition t_(max) (h) C_(max) (nmol/ml)(h * nmol/ml) Complex Fasted 0.50 ± 0   1064 ± 219  1575 ± 339Abiraterone Complex High fat 0.38 ± 0.13 1086 ± 433  1345 ± 435Abiraterone meal Zytiga Fasted 1.06 ± 0.54 76 ± 38 138 ± 75 Zytiga Highfat 0.81 ± 13   443 ± 215  773 ± 300 meal

Table 7 shows pharmacokinetic parameters following the oraladministration of Zytiga of the Complex Abiraterone acetate formulationto beagle dogs. N=4, dose: 50 mg.

Pharmacokinetics in Healthy Man

Ten healthy male volunteers between the ages of 45 and 65 were enrolledin a clinical pharmacokinetic study where 200 mg of the Complexabiraterone formula was administered orally in the fasted and in the fedstate. Maximal plasma abiraterone concentrations were detected at 0.5hour indicating immediate absorption of the active ingredient from theformula. No significant increase was observed in the plasmaconcentrations in the fed state when compared to the fasted state,actually, there plasma concentration were lower in the fed state atearly time points, while were practically identical after the 4 hourtime point (FIG. 20). AUC_(inf) and C_(max) values calculated from thecurves and variability of exposure and food effect was calculated formthese pharmacokinetic parameters and compared to published clinicalpharmacokinetic data for 1000 mg Zytiga (Table 8). AUC in the fastedstate for the 200 mg dose of the Complex Abiraterone Acetate was 80% ofthe 1000 mg dose for Zytiga, therefore, significant dose reduction ispossible using the Complex Abiraterone Acetate formula. Also, the verylarge positive food effect was eliminated which shows that therequirement for Zytiga to be taken for an empty stomach was eliminated.The variability of exposure was also significantly reduced. Theelimination half life was identical to data published for Zytiga (EMEAAssessment Report For Zytiga (abiraterone)).

TABLE 8 shows pharmacokinetic parameters following the oraladministration of 1000 mg Zytiga (EMEA Assessment Report For Zytiga(abiraterone), Acharya et al., 2012 and Attard et al., 2008.) or 200 mgComplex Abiraterone acetate formulation to 10 healthy male volunteers inthe fasted and in the fed state. COMPLEX COMPLEX ZYTIGA ABIRATERONE,ABIRATERONE, FASTED* FASTED FED Dose (mg) 1000 200 200 AUC_(last) (ng *h/ml) 503 (100) 399 (80) 295 (59) (% of 1000 mg Zytiga) C_(max) (ng/ml)93.5 206 72 Variability (AUC_(last) 0.5 0.3 0.2 CV %) Variability(max/min 9 2.3 2.2 AUC_(last)) Food effect (fed/fasted 5 0.74AUC_(last)) t_(1/2) (h) 16 15 13

Enteric Coated Tablet Containing Complex Abiraterone Acetate

Freeze dried complex Abiraterone acetate formulation of the presentdisclosure was dry granulated via slugging or roll compaction in orderto obtain powder with sufficient flowability. The particle size of thegranulated complex Abiraterone acetate formulation was between 160-320μm. The granulated complex Abiraterone acetate formulation was thenblended with lactose-monohydrate, microcrystalline cellulose as fillers,crosscarmellose sodium as disintegrant and sodium-deoxycholate asabsorption supporting agent (Table 9).

TABLE 9 shows Composition of the complex Abiraterone tablets.Composition of complex Abiraterone acetate granulation Granulatedcomplex Abiraterone active ingredient 31.32 w/w % Lactose-monohydrate(Flowlac 100) filler 31.32 w/w % Microcrystalline-cellulose (Vivapurfiller 15.66 w/w % 101) Croscarmellose sodium disintegrant 14.99 w/w %Sodium-deoxycholate absorption  6.71 w/w % supporting agent

The powder mixture containing granulated complex Abiraterone acetateformulation of the present disclosure was compressed into tablets with50 mg dose strength. Disintegration time of the tablets containingcomplex Abiraterone acetate formulation in simulated intestinal fluidwas less than 5 minutes. The cores of tablets containing complexAbiraterone acetate formulation were coated with anionic copolymer basedon methacrylic acid and ethyl acrylate.

From the foregoing description, one skilled in the art can easilyascertain the essential characteristics of this invention, and withoutdeparting from the spirit and scope thereof, can make various changesand modifications of the invention to adapt it to various usages andconditions.

What is claimed is: 1.-15. (canceled)
 16. A process for the preparationof a stable complex with improved physicochemical characteristics andenhanced biological performance comprising a) Abiraterone acetate; b) atleast one complexing agent chosen from polyethylene glycol glyceridescomposed of mono-, di- and triglycerides and mono- and diesters ofpolyethylene glycol, hydroxypropylcellulose, poloxamers,vinylpyrrolidone/vinyl acetate copolymer, polyethylene glycol,poly(2-ethyl-2-oxazoline), polyvinylpyrrolidone, block copolymers basedon ethylene oxide and propylene oxide, poly(maleic acid/methyl vinylether), polyvinyl caprolactam-polyvinyl acetate-polyethylene glycolgraft copolymer, polyoxyl 15 hydroxystearate, ethylene oxide/propyleneoxide block copolymer, polyvinyl alcohol-polyethylene glycol graftcopolymer, d-alpha tocopheryl polyethylene glycol 1000 succinate andcaprylic/capric triglycerides; and c) optionally, pharmaceuticallyacceptable excipients; wherein said complex has a particle size lessthan 600 nm, and possesses one or more among the following features: a)it is instantaneously redispersible in physiological relevant media; b)it has increased dissolution rate compared to Zytiga; c) it is stable insolid form and in colloid solution and/or dispersion; d) its apparentsolubility in water is of at least 0.6 mg/mL, e) it has a PAMPApermeability of at least 0.5*10⁻⁶ cm/s when dispersed in distilledwater, which does not decrease in time at least for 3 months; f)exhibits no positive food effect (fed/fasted ration is under 1.25) whichallows significant dose reduction and the abandoning of the requirementof taking the drug on an empty stomach; and g) the variability ofexposure is significantly reduced when compared to Zytiga, said processcomprising the step of mixing a solution of the active agent and atleast one complexing agent and optionally one or more pharmaceuticallyacceptable excipient in a pharmaceutically acceptable solvent with anaqueous solution containing optionally least one pharmaceuticallyacceptable excipient.
 17. The process as recited in claim 16, whereinsaid process is performed in a continuous flow instrument.
 18. Theprocess as recited in claim 17, wherein said continuous flow instrumentis a microfluidic flow instrument.
 19. The process as recited in claim16, wherein said pharmaceutically acceptable solvent is chosen fromwater, methanol, ethanol, isopropanol, n-propanol, acetone,acetonitrile, dimethyl-sulfoxide, tetrahydrofuran, or combinationsthereof.
 20. The process as recited in claim 19, wherein saidpharmaceutically acceptable solvent is a combination of water andtetrahydrofuran.
 21. The process as recited in claim 16, wherein saidsolvents are miscible with each other and the aqueous solvent comprises0.1 to 99.9% weight of the final solution. 22.-25. (canceled)